Social media and politics
If you think social media is still optional in electoral politics, this Forbes article is a must read. It details the social media strategy that Jared Kushner used to target supporters, raise money, identify topics that resonated, even plan rally locations that ultimately helped elect his father-in-law president. (And Kushner himself has never posted a single tweet. )

Some takeaways:

Television and online advertising? Small and smaller. Twitter and Facebook would fuel the campaign, as key tools for not only spreading Trump's message but also targeting potential supporters, scraping massive amounts of constituent data and sensing shifts in sentiment in real time.

...For those who can't understand how Hillary Clinton could win the popular vote by at least 2 million yet lose handily in the electoral college, perhaps this provides some clarity. If the campaign's overarching sentiment was fear and anger, the deciding factor at the end was data and entrepreneurship.